WPF TreeViewItem自定义样式圆角

Question

[我试图在整个TreeViewItem上放置圆角。不只是“页眉”部分，还可以直接修改默认样式模板。

<ControlTemplate TargetType="{x:Type TreeViewItem}">
   <!--<Border CornerRadius="25" BorderBrush="Black" BorderThickness="1" Visibility="Visible">-->
          <Grid Background="DeepPink" Margin="0 5" x:Name="grid">
              <ToggleButton x:Name="Expander" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ExpandCollapseToggleStyle}"/>
              <Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.Column="1" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true">
                   <ContentPresenter x:Name="PART_Header" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
              </Border>
              <ItemsPresenter/>
           </Grid>
    <!--</Border>-->
</ControlTemplate>

我删除了一些细节以使其更具可读性。问题是，一旦我将Border放在网格周围，整个功能就消失了。它不再扩展了。

可以这样做吗？如何获得圆角并保持功能？

Answer 1

您在示例中删除了XAML的某些部分，但是也许这些部分对于调查问题很重要。

这里是一个对我有用的控制模板：

<ControlTemplate TargetType="{x:Type TreeViewItem}">
    <Border Margin="4" BorderBrush="Red" BorderThickness="1" CornerRadius="10">
        <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition MinWidth="19" Width="Auto" />
            <ColumnDefinition Width="Auto" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition />
        </Grid.RowDefinitions>
        <ToggleButton x:Name="Expander" ClickMode="Press"
                IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}"
                Style="{StaticResource ExpandCollapseToggleStyle}" />
        <Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}"
                BorderThickness="{TemplateBinding BorderThickness}"
                Background="{TemplateBinding Background}" Grid.Column="1"
                Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true">
            <ContentPresenter x:Name="PART_Header" ContentSource="Header"
                    HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                    SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
        </Border>
        <ItemsPresenter x:Name="ItemsHost" Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="1" />
    </Grid>
    </Border>
    <ControlTemplate.Triggers>
        <Trigger Property="IsExpanded" Value="false">
            <Setter Property="Visibility" TargetName="ItemsHost" Value="Collapsed" />
        </Trigger>
        <Trigger Property="HasItems" Value="false">
            <Setter Property="Visibility" TargetName="Expander" Value="Hidden" />
        </Trigger>
        <Trigger Property="IsSelected" Value="true">
            <Setter Property="Background" TargetName="Bd"
                    Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}" />
            <Setter Property="Foreground"
                    Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}" />
        </Trigger>
        <MultiTrigger>
            <MultiTrigger.Conditions>
                <Condition Property="IsSelected" Value="true" />
                <Condition Property="IsSelectionActive" Value="false" />
            </MultiTrigger.Conditions>
            <Setter Property="Background" TargetName="Bd"
                    Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightBrushKey}}" />
            <Setter Property="Foreground"
                    Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightTextBrushKey}}" />
        </MultiTrigger>
        <Trigger Property="IsEnabled" Value="false">
            <Setter Property="Foreground"
                    Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
        </Trigger>
    </ControlTemplate.Triggers>
</ControlTemplate>

我使用了默认的控件模板，并在外部网格周围添加了边框。

这里是结果：